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Battery trunk relocation options

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Quote: Alloy flexes more in tension than steel and steel flexes more than cold rolled seamless tube used in certified roll cages, alloy brace = show brace.

 

The modulus of elasticity of steel alloys, from low carbon cold rolled to high carbon tool steels, ranges no more than about 5%; with tool steels, for example Chrome-Molybdenum (4130 and 4340) being the stiffest by only a very small margin.  

Click on  https://www.amesweb.info/Materials/Modulus-of-Elasticity-Metals.aspx  and scroll down to Steel Alloys.

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(edited)

  Aluminum, steel and other exotic materials can be made to operate in similar ways. It is just a matter of tubing diameters, thicknesses and material choice.

Edited by evil02

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(edited)
On ‎12‎/‎27‎/‎2018 at 8:34 AM, uai said:

I went for under the rear seat - took a lot of shrinking to make the floor bend evenly down. It looks a bit horrible with primer and phosphate but will be nice once clean and painted.

If I went for the trunk I would have made it Schnitzer style as I have a period 100 liter alloy tank where most put their Batteries.

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I had a similar solution - battery under the passenger side seat in back. Cut a flap in the floor pan, bent down and welded in three gussets to form a box, put a 1/4 inch mud flap rubber pad underneath. I used an original red top for 14 years! 

 

Cables- ran 2/0 welding cable under the right side seat up to the firewall, used an existing hole with grommet to run +12V to the starter relay; grounded battery to the seat belt mounting bolt in back. I ran 4 gauge from the starter to a new battery bus under the headlight / horn relays for power distribution, alternator, all battery feeds to key, fuse box, extra relays, etc.  Also a great jumper cable point. 

 

Coincidentally, I also built a spare tank very similar to yours, 16ga, stainless steel, held 28+ gallons (106 liters).  Had all penetrations in the top so no leaks.  Wired the fuel level sender and tank selector solenoid valve through a DPDT switch under the dash so I could read either tank level on the dash in the original fuel level gauge when I switched tanks!  Electric fuel pump fed the carbs, blanking plate replaced the mechanical pump.   With both tanks filled, I had an over 1,000 mile (1600 km) range between fuel stops (stops for Pilot Relief as needed).

Edited by MoBrighta
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On 12/27/2018 at 12:48 PM, NYNick said:

Here's my Lithium install.

20181208_135419.jpg

 

Any updates on how your lithium is holding up so far?

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(edited)

Works like a charm. Zero issues.

Edited by NYNick
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FYI - Just swung by the local Pick-n-Pull and grabbed the positive cable to the trunk, negative cable, terminal block, and positive cable from block to starter from an E46 for FOUR DOLLARS. Yes, $4! That also included a Bosch coil from a Volvo. 

 

Ok, ok, $6. I had to pay $2 to get in. Took about 15min to pull it. I just chopped the starter cable because it was way longer than I needed and I didn't feel like skinning my knuckles. 

 

33462FCB-D7BB-445D-BD7C-597EF264CE98.thumb.jpeg.024903d0adde263abc482488904fbdad.jpeg

Edited by Mucci
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I want to relocate my battery to the trunk and would like to use welding wire to run through a fuse to a terminal block in the engine compartment. I'm not sure what size of wire to get (and the fuse). The #2 wire is rated for about 200 A at 50 feet. The wire length will be much less than 50' and the starter shouldn't shouldn't draw current for more than a few seconds. Is a #2 welding wire suitable, or should I go with something larger? Also, for the fuse should it be sized based on the rated current of the wire (200A)? I guess... will that fuse blow if the starter briefly draws more than 200 A?

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20 minutes ago, cgates30 said:

I want to relocate my battery to the trunk and would like to use welding wire to run through a fuse to a terminal block in the engine compartment. I'm not sure what size of wire to get (and the fuse). The #2 wire is rated for about 200 A at 50 feet. The wire length will be much less than 50' and the starter shouldn't shouldn't draw current for more than a few seconds. Is a #2 welding wire suitable, or should I go with something larger? Also, for the fuse should it be sized based on the rated current of the wire (200A)? I guess... will that fuse blow if the starter briefly draws more than 200 A?

 

What I've read is 4 gauge or thicker is the ticket. In my search for the cheapest solution 25' 4 gauge jumper cables can be had for about $16 shipped on Amazon. Home Depot wanted about $1/ft. For reference the nose of the car to the trunk is about 13' A to B. 

 

Jumper cable and welding cable is pretty much the same "flexible" thin strand wire. 

 

There isn't typically a fuse between the battery and starter on cars. 

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The first number is no of wire strands and strand thickness; welding and other home type cables has less for same diameter cable and very different sheeth not designed for automotive use. The thick strands fracture with vibration these can easily peirce through its sheeth causing premature failure for same reason i avoid using old cables.

 

Going by wire guage doesn't tell you the info you need.

 

The correct cable should be min

322/0.30 25mm², 10.0mm OD, 170A

 

Recommended

539/0.30 40mm², 12.7mm OD, 300A

 

 

ALWAYS put inline fuse in NEAR battery. The fuse should be smallest you can get away with with all electrics on (cold start wipers lights heater everything on full)

 

Negative cable should be identical to power cable in size with shortest path to body as possible. Always add smaller gauge wire for local grounds for switch gear, lights ect.. nothing wrong with too many grounds.

 

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I recommend using marine type cables instead of welding or other "home use" cable typically found at big box hardware stores. The marine cables are more flexible for routing thru the chassis.   You can find this type along with suitable terminal ends at West Marine stores.

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I went to an Interstate Battery dealer and asked if they had any 0 gauge cable. The guy went in the back, cut it to length for me and attached connectors with shrink wrap. $20. See the pic of my under seat location above for my Li-Pho.

 

Batteries can be so much lighter these days, I have no idea why anyone would put them in the trunk anymore.

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3 hours ago, ShakeyC said:

The correct cable should be min

322/0.30 25mm², 10.0mm OD, 170A 

 

Recommended

539/0.30 40mm², 12.7mm OD, 300A

Wow, I didn't realize there would be so many strands in a 10 mm OD cable. Is the 25 mm2 the cross section of the strand bundle? And 10 mm the diameter including the insulation?

 

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yes 25mm2 is cross section area and 10mm OD includes insulation.

 

0.03 (single coppper strand) X 322 (strands) = 9.66mm diameter 

9.66-10mm OD = 0.34mm  pvc insulation for thin wall automotive cables.

 

 

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I just got my AG battery, 3 lbs. I already had removed the original tray because I was going to mount in the trunk, but that doesn't make sense with a 3 lb battery, the long cables would weigh more than that.
I'll mount it close to the stock location
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